Dynamic modelling of air temperature in breathing zone with stratum ventilation using a pulsating air supply

2021 ◽  
pp. 108697
Author(s):  
Xue Tian ◽  
Zhang Lin
Keyword(s):  
Air Temperature ◽  
Dynamic Modelling ◽  
Breathing Zone ◽  
Air Supply

scholarly journals Optimisation of Tray Drier Microalgae Dewatering Techniques Using Response Surface Methodology

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2327 ◽  
Author(s):  
Ruth Anyanwu ◽  
Cristina Rodriguez ◽  
Andy Durrant ◽  
Abdul Olabi
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Air Temperature ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Slight Effect ◽  
Air Velocity ◽  
Independent Variables ◽  
Air Supply ◽  
Central Composite

The feasibility of the application of a tray drier in dewatering microalgae was investigated. Response surface methodology (RSM) based on Central Composite Design (CCD) was used to evaluate and optimise the effect of air temperature and air velocity as independent variables on the dewatering efficiency as a response function. The significance of independent variables and their interactions was tested by means of analysis of variance (ANOVA) with a 95% confidence level. Results indicate that the air supply temperature was the main parameter affecting dewatering efficiency, while air velocity had a slight effect on the process. The optimum operating conditions to achieve maximum dewatering were determined: air velocities and temperatures ranged between 4 to 10 m/s and 40 to 56 °C respectively. An optimised dewatering efficiency of 92.83% was achieved at air an velocity of 4 m/s and air temperature of 48 °C. Energy used per 1 kg of dry algae was 0.34 kWh.

Thermal comfort analysis of radiant cooling panels with dedicated fresh-air system

2020 ◽  
pp. 1420326X2096114
Author(s):  
S. Y. Qin ◽  
X. Cui ◽  
C. Yang ◽  
L. W. Jin
Keyword(s):  
Relative Humidity ◽  
Surface Temperature ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Indoor Air ◽  
Area Ratio ◽  
Human Thermal Comfort ◽  
Air Supply ◽  
Radiant Cooling ◽  
Air System

Radiant system has been increasingly applied in buildings due to its good thermal comfort and energy-saving potential. In this research, a simplified predicted mean vote (PMV) model and sensible cooling load equation were proposed based on human thermal comfort. Simulations were carried out using Airpak to explore relationships among thermal comfort characteristics, design and operation parameters. Results show that radiant surface temperature, fresh-air supply temperature and the area ratio are correlated approximately linearly with the indoor air temperature, while the relative humidity has little effect on the indoor air temperature. The indoor air velocity in the simulated environment was no more than 0.15 m/s, satisfying the requirements of limit values in the occupied zone. The results indicate that the optimum radiant surface temperature ( tc) is 19°C to 23°C when fresh-air supply temperature ( ts) is 26°C. The relative humidity ( φ) should be maintained at 50% to 70%, and the area ratio of radiant panels to total surfaces ( k1) should be kept within 0.15 to 0.38 when the radiant surface temperature is 20°C and the fresh-air supply temperature is 26°C. The simplified PMV model and the sensible load equation can provide reference for panel design based on characteristics of radiant cooling panels with a dedicated fresh-air system.

Research on Desk Personalized Ventilation in Winter Based on CFD

2015 ◽  
Vol 9 (1) ◽  
pp. 411-415
Author(s):  
Liu Fei ◽  
Zhang Dongliang
Keyword(s):  
Numerical Simulation ◽  
Energy Saving ◽  
Air Temperature ◽  
Human Body ◽  
Air Conditioning ◽  
Simulation Software ◽  
Supply Angle ◽  
Air Supply ◽  
Personalized Ventilation ◽  
Ventilation Scheme

The excellent desk personalized ventilation scheme is found in this paper by the way of comparing the four winter air supply schemes, basing on the numerical simulation software of CFD. We find that air supply quality and air supply angle are both the important factors to personalized ventilation individual comfort in winter. The air temperature and velocity surrounding the human body of the excellent desk personalized ventilation scheme are discussed. It comes to the conclusions that under simulated conditions the excellent desk personalized ventilation scheme can better satisfy the human body comfort on the surrounding air temperature and healthy than the traditional air conditioning, and it is easier to achieve energy saving too.

Numerical study of different ceiling-mounted air distribution systems for a virtual classroom environment

2016 ◽  
Vol 26 (10) ◽  
pp. 1382-1396 ◽  
Author(s):  
Eusébio Z. E. Conceição ◽  
Cristina I. M. Santiago ◽  
Hazim B. Awbi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Distribution Systems ◽  
Numerical Study ◽  
Virtual Classroom ◽  
Comfort Level ◽  
Air Distribution ◽  
Air Supply ◽  
Distribution Index

This paper presents a comparative numerical study of different ceiling-mounted-localized air distribution systems placed above students in a virtual classroom in summer conditions. The influence of four different ceiling-mounted-localized air distribution systems, using vertical descendent jets, on the thermal comfort, local thermal discomfort, and air quality levels was numerically evaluated. The air distribution index, developed previously, was used for non-uniform environment. This index considers the thermal comfort level, air quality level, effectiveness for heat removal, and effectiveness for contaminant removal. Numerical simulations were conducted for a virtual classroom equipped with one of four different ceiling-mounted-localized air distribution systems and with 6 desks, 6 or 12 students, and 2 upper airflow outlets. Inlet air supply temperature of 20 and 24℃ and an outdoor air temperature of 28℃ were used. The simulation results show that the air supply system having a vertical air jet placed at 1.8 m above the floor level (Case III), and with an inlet area of 0.01 m2 and a supply air velocity of 3 m/s would represent the best option in comparison with other air supply methods. In general, the air distribution index value decreases with an increase in inlet air temperature and the number of occupants. The air distribution index values are highest for Case III representing a classroom with 6 or 12 occupants with an inlet air temperature of 20 or 24℃.

scholarly journals RESULTS OF INSPECTION OF THE STATE OF PROVIDING THE MICROCLIMATE IN THE PIG FARM WITH A NEGATIVE PRESSURE VENTILATION SYSTEM

2021 ◽  
pp. 168-177
Author(s):  
Vitalii Yaropud ◽  
Yelchin Aliyev
Keyword(s):  
Air Temperature ◽  
Negative Pressure ◽  
Cooling System ◽  
Ventilation System ◽  
Air Cooling ◽  
Negative Pressure Ventilation ◽  
Normal Limits ◽  
Air Supply ◽  
Air Cooling System ◽  
Pig Farm

The most popular microclimate system today is based on a negative pressure ventilation system. Because it is easier to use and consumes less energy than any other forced ventilation system. The purpose of the research is to inspect the room for keeping piglets on rearing with a negative pressure ventilation system to identify shortcomings and deviations of the microclimate parameters necessary for further improvement. According to the results of the inspection of the rearing room for piglets, it was found that according to the existing system of negative pressure in the rearing room for piglets, most indicators (air velocity, ammonia, carbon dioxide, hydrogen sulfide, oxygen) are within normal limits. According to the results of the inspection of the room for keeping piglets for rearing with a negative pressure microclimate system, it was found that the air temperature in the room does not meet the recommended limits and reaches 30 °C, while the maximum recommended temperature for piglets for fattening is 20 °C. The air temperature is uneven along the length of the room, which is caused by uneven air supply from the vents. According to the results of the inspection of the room for piglets with a negative pressure microclimate system, it was found that the relative humidity at the height of the animals is higher than the recommended norms and reaches 95%, while the recommended humidity for piglets for fattening is not more than 80%. According to the results of the inspection of the room for keeping piglets for rearing with a negative pressure microclimate system, it can be stated that it is necessary to improve the air cooling system and replan the ventilation ducts of the ventilation system to ensure even air flow.

Ventilation Measurement and Simulation Optimization for Aerobic Composting Workshop of a Large Sludge Treatment Engineering

2012 ◽  
Vol 170-173 ◽  
pp. 2727-2731
Author(s):  
Kai Zhen Zhu ◽  
Jian Fei Zhang ◽  
Shuang Jia ◽  
Xu Du ◽  
Li Juan Zhang
Keyword(s):  
Mechanical Ventilation ◽  
Energy Consumption ◽  
Simulation Optimization ◽  
Breathing Zone ◽  
Aerobic Composting ◽  
Ammonia Content ◽  
Sludge Treatment ◽  
Ventilation Condition ◽  
Air Supply ◽  
Better Than

Based on measured ventilation condition in the built aerobic composting plant of large sludge treatment engineering,using the methord of CFD, four kinds of scheme for the new aerobic composting plant were analysed,which contain two types of ventilation(natural air supply mechanical exhaust and mechanical air mechanical ventilation)and two kinds of supply air rates (4x105m3/h and 8x105m3/h). Studies have shown that the methord of mechanical air supply and exhaust is better than the original natural air mechanical exhaust in this plant; The methord of mechanical air supply and exhaust is recommended to reduce ammonia content for personal breathing zone and ventilation energy consumption.

scholarly journals Development of an air conditioning system with individual regulation of temperature and air flow rate in a compartment of a passenger car

2021 ◽  
Vol 80 (1) ◽  
pp. 30-34
Author(s):  
G. M. STOYAKIN ◽  
A. V. KOSTIN ◽  
S. N. NAUMENKO
Keyword(s):  
Air Temperature ◽  
Flow Rate ◽  
Air Conditioning ◽  
Air Flow ◽  
Three Dimensional ◽  
Air Flow Rate ◽  
Passenger Cars ◽  
Air Conditioning System ◽  
Air Supply ◽  
Individual Regulation

Maintaining optimal parameters of the microclimate in the car along the route is the most important requirement for the passenger’s travel. In the 1st class passenger cars, maintaining optimal microclimate parameters is achieved through the operation of the air conditioning system, which provides individual regulation of the air temperature in each compartment. Individual air temperature control systems used in air conditioning systems are divided into two groups: active and passive.The article proposes for consideration a combined active-passive system with a separate air supply with a lower and higher temperature compared to the temperature maintained in the compartment and the installation of individual induction terminals, which makes it possible to increase the efficiency of individual regulation of air parameters in the compartment.To assess the uniformity of temperature distribution and air flow rate over the car volume with the proposed control scheme, a three-dimensional modeling of the distribution of these parameters in the compartment was carried out on the basis of Autodesk CFD software.The given simulation results indicate the uniformity of temperature and air flow rate distribution over the compartment volume, which makes it possible to characterize the proposed system as sufficiently energy efficient, easy to operate and reliable in operation.

The Study of Indoor Thermal Environment Characteristics of Office Building Effected by Stratum Ventilation

2014 ◽  
Vol 556-562 ◽  
pp. 803-806
Author(s):  
Ze Qin Liu ◽  
Zhen Jun Zuo ◽  
Tai Shun Liu
Keyword(s):  
Thermal Comfort ◽  
Thermal Stratification ◽  
Thermal Environment ◽  
Vertical Direction ◽  
Ventilation Rate ◽  
Office Building ◽  
Breathing Zone ◽  
Indoor Thermal Environment ◽  
Human Thermal Comfort ◽  
Air Supply

A typical office building with stratum ventilation as the research object was studied in this paper. CFX Fluid Computation software was used to numerical simulate the characteristics of indoor thermal environment effected by air speeds under 19°C supply air temperature and 8 ventilation rate. The numerical simulate results showed that, the obvious thermal stratification occurred in the vertical direction. Such thermal stratification met the demands of building energy conservation and the human thermal comfort. In this paper, the velocity coefficient and the temperature coefficient were used to evaluate thermal comfort. From the results of the numerical simulation, it could be seen that when the supply air speeds were controlled between 0.5m/s to 0.9m/s, the thermal comfort, as well as the air supply efficiency in the human activity area was relative satisfactory. With the constant fresh air ventilated to the breathing zone, the air quality could be improved.

Cooling Systems for Refuge Alternatives in Hot Mine Conditions

2018 ◽  
Author(s):  
Lincan Yan ◽  
David Yantek ◽  
Miguel Reyes ◽  
Nicholas Damiano ◽  
Justin Srednicki ◽  
...  
Keyword(s):  
Air Temperature ◽  
Elevated Temperatures ◽  
Storage Capacity ◽  
Cooling System ◽  
Cooling Capacity ◽  
Cooling Systems ◽  
Air Conditioning System ◽  
Test Methodology ◽  
Air Supply ◽  
Entire Duration

The accumulated heat and humidity inside occupied refuge alternatives (RAs) can impose risk of heat stress to the occupants. The accumulated heat could be from the metabolic and environmental sources. For hot mines, the high ambient temperature makes it more difficult to dissipate heat accumulated inside the RA. A cooling system is then needed to reduce the interior heat and humidity. Two types of cooling systems were tested out for their cooling capacity. One cooling system is a portable, battery-powered, air conditioning system and the other is a portable cryogenic air supply. During the testing, the mine air temperature surrounding the RA was elevated to and maintained at 85°F to simulate hot mine environment. The tests demonstrated that both cooling systems were able to control the air temperature inside the RA even though they did not last the entire duration of a 96-hour test. This paper provides an overview of the test methodology and findings as well as guidance on improving the performance of both cooling systems, including: optimizing the cooling cycle for the battery-powered AC system and increasing the flow rate and tank storage capacity for the cryogenic system. The information in this publication is useful for RA manufacturers and mines to develop the cooling systems that will enable providing the life sustaining environment in mines with elevated temperatures.

scholarly journals Experimental research on a hot air generator working on the TLUD principle

2019 ◽  
Vol 112 ◽  
pp. 01006
Author(s):  
Ioan Pavel ◽  
Radu-Iulian Rădoi ◽  
Gabriela Matache ◽  
Ana-Maria Carla Popescu ◽  
Ioan Caba
Keyword(s):  
Data Acquisition ◽  
Temperature Variation ◽  
Air Temperature ◽  
Experimental Research ◽  
Temperature Sensors ◽  
Optimum Temperature ◽  
Hot Air ◽  
Air Supply ◽  
Data Acquisition Board ◽  
Key Points

The current paper presents the processes of data acquisition and air temperature monitoring in the key points of a hot air generator working on the TLUD principle, which uses temperature sensors, a data acquisition board and an application developed in LabView that numerically and graphically displays temperature variation during burning. The results of the monitoring were obtained on an experimental model, developed by research scientists at INOE 2000-IHP. The data acquired is then used to establish the algorithm for opening the air supply valves for gasification and combustion air, in order to optimize combustion by maintaining the optimum temperature at the funnel.

Sign in / Sign up

Export Citation Format

Share Document